I would like to control the relay of my MPPT charge controller with Node Red via Can, e.g. to allow my heat pump to charge the hot water tank in summer if the solar power is sufficient. Unfortunately, this is not possible at the moment.
asked
Are there plans to extend the firmware of the MPPT charge controllers to control the relay?
Why not use the relais on the CerboGX?
At this moment I have only MultiPlus2Gx in use, but I have 7 MPPT Charge Controllers in my system;-(
The MultiPlus-II GX has also a relais in it.
Since i do not kow which MPPTs you have, I can tell you, that all 150/250 Volt versions can work independantly.
I have now one SmartSolar MPPT 150/70 (1,86kWp) and two SmartSolar MPPT 250/100 (each 2,05kWp) and I use all three relais to switch things.
1) Set to "High Voltage" and switch on, when the Voltage exceed 28,8V (my Batteries have an Absorbtion Voltage of 29,6V but I do not want to waist energy in the summer, and switch a 2kW heating element on, which pump heat into the ground)
2) Set to "High Voltage" 29,4V and switch on an additional 2kW Heating Element
3) Set to "Float" and show me currently only a light that I know I can wash clothes or bake a cake...
Have fun
Hi
@Michelle Konzack,
I have 250/70, 250/85 and 150/70 at my system. If there is no other possibility, I would do that the same way. Bu to control e.g. my safety relais, I would need a much more complex algorithm, that I already programmed in Node Red.
Oh, I forgot, my MPPTs are synced with VE.Can
Hi @Thomas Manthey ,
It is a known limitation that the MPPT relays cannot be controlled by Node Red yet.
I expect it will be added at some point, but there is no timeline (that I know of) yet.
Hi @Guy Stewart (Victron Community Manager) ,
thank you for your replay. Then I have to focus on my CerboGX with 2 relays. I want to use it anyway for having potential divided Ve.direct interfaces. With Multi2Gx and Ve.direct2usb adapters there are problems with a stable connection of the smart shunts.
Hi @Thomas Manthey,
There is also another potential path coming to enable more relay interfaces to control for Node Red users.
Please keep your eyes on the Victron blog and Victron Professional news, and I will try to remember to post back here when it's ready.
Any teasers or hints you might be able to drop? For example, would you be able to disclose if this will be for existing equipment with relays such as MPPT or multi's/quatro's, or hopefully a new plug and play relay module in the works? I know you can't always give details about things in r&d but a feller can hope, lol.
Hi @Guy Stewart (Victron Community Manager) ,
there may be another possibility: Since the software from Victron is open source, reading the current relay status already works and I also programme microcontroller control units for a living, I assume that only another Can service is required to write the relay status.
Where can I find the software for the MPPT solar chargers?
Only VenusOS is open source, not the Firmware for MPPTs or even Charging-Inverters
But if node red output node solarcharger relay control doesn't work, why victron build it into NodeRed?
Users try to use it and spend a long time trying to figure out why it doesn't work.
The MPPT's relay are the only ones that support 230V AC!
The reason may be, that some devices e.g. like CerboGx support the using of the relais. At this moment for me it's a little bit pity, because of 7 unusable relais outputs. So I must wait for the Charger-Extention at some day.
You can not switch high load with the relais on the MPPTs. It is only 4A max. And, if you have excess Solar power, I would not even think on loading the relais with 4A, because the MPPTs are very hot.
Why not simply use external relais where you can choose even 125A relais with 1 or 3 phases?
I case something went wrong, you do not kill the relais or even the board in the MPPTs.
I know. I switch another contactor with the cerbo (MPPT) relay. It is easier to use 230V for switching, than a relay that is switched with 48V DC.
All relays on the Cerbo do not support 230V and are implemented by Victron in NodRed (but do not work there).
There are certainly many options. It is best to work with the simple and available things.
My plan was to switch relays that are able to switch up to 3x380V/63A maxinum with my system switching voltage of 24V (generated by a DC-DC converter). For that purpose the 4A are more than enough.
The first thing I want to include is a safety relays in every generator connection box that makes a shortcut on every solar cluster (250V/25A max.), if there is no switching voltage supplied. If there is a problem with the solar generators or a fire, I only have to push the big red button. And no voltage and therefore power is forcing the fire anymore and the system is free from dangerous voltages. The shortcut current of my solar panels is about 11,5A and they even get no damage during a shortcut.
You can always use 24/48 Vdc controlled by the cerbo relays to switch an external relay of suitable rating to control your load. Using external relays is best practice, to avoid faulting an expensive unit if the internal relay fails.
